Sri Lankan President Maithripala Sirisena on Thursday suspended parliament until next month in a shock move amid a deepening power struggle between him and his unity government’s prime minister.

A government decree quoted the president as stating that he had halted parliament’s meetings “with effect from midnight” on Thursday under article 70 of the constitution.

The move, scheduled to last until May 8, came hours after at least 16 Sirisena loyalists, including six cabinet ministers, said they would leave the troubled coalition.

Relations between the rival groups in the unity government have soured after both suffered losses in February’s local council elections.

Prime Minister Ranil Wickremesinghe’s United National Party (UNP) had increased pressure on the followers of Sirisena – who voted against Wickremesinghe in a recent no-confidence motion – to resign.

Parliament had been expected to meet again next Thursday and presidential officials declined to comment on the reason for the suspension.

“We have been surprised by the announcement,” one government legislator who requested anonymity said.

Just hours before he announced the suspension of parliament, Sirisena had appointed acting ministers to the positions of those who quit the Cabinet.

Wickremesinghe last week won the motion of no confidence moved by the joint opposition and backed by Sirisena’s ministers.

With the help of minority Tamil and Muslim parties, the premier defeated the motion – dealing a blow to Sirisena, who had campaigned for Wickremesinghe to stand down to allow him to appoint a prime minister of his choice.